This invention relates to dye-forming electrothermographic materials and processes which enable formation of dye images without the need for silver compounds.
Electrographic recording materials and processes and electrically activatable recording materials and processes which involve production of a visible image in a charge-sensitive recording element are known. Examples of such recording materials and processes are described in, for example, U.S. Pat. Nos. 4,234,670 and 4,343,880. Such recording materials and processes involve imagewise exposure of a charge-sensitive recording element to electric current to form a developable image in the charge-sensitive recording element followed by processing, preferably thermal processing, to form a silver image or a silver image and a dye image. A problem with these electrically activatable recording materials has been that they have required the presence of silver image-forming compounds. They have not enabled dye images, especially multicolor dye images from electrothermographic elements without incorporated silver image-forming compounds.
While dye-forming electrothermographic materials are described in, for example, U.S. Pat. No. 4,343,880, such materials require silver image-forming compounds.
A continuing need has existed for a dye-forming electrothermographic element and process which enable formation of a dye image, particularly a multicolor image, and which (a) avoid the need for silver image-forming compounds in imaging, (b) enable roomlight handling of the recording materials, and (c) avoid the need for conventional processing solutions and baths.